DE1905198C3 - Process for producing an embossing roller for thermoplastic plastic films - Google Patents

Description

The invention relates to a method for producing an embossing roller for thermoplastic plastic films, b ^ i which one on a cylindrical mandrel with a a synthetic resin is applied to the outer surface with an identical shape to the embossing roller to be produced and hardens at elevated temperature to form an elastic negative model that is removed from the mold core separates, concentrically inserts a roller core into the negative model, leaving an annular space free, in A synthetic resin is poured into the annular space, the synthetic resin under heat to form an elastic embossing roller jacket hardens and separates the roller core together with the embossing roller shell from the negative model

In a known method of this type (AT 28 476), a tube shape is used as the negative model used before the filling of the later embossing roller shell forming plastic in a suitable Zylirtderförrrt, z. B. in a sieve jacket

inserted and brought to the full concern to this. After the resin has been filled and hardened the negative model is turned inside out to separate the negative model from the embossing roller shell deducted.

This turning inside out can not only damage the negative model by overstretching it, but it can also affect the surface of the embossing roller jacket. Apart from this, the production of a tubular negative model is also disadvantageous in this process, as a paste-like plastic, which remains elastically stretchable after solidification, is applied to a congruent model of the roller to be produced, which bears the negative of the embossed pattern, and made to solidify then the seamless tube model created in this way is pulled off the roller model with elastic stretching. Here, too, the tube model or negative model is already stretched to a very great extent, so that this rough type of demolding can impair the sensitive surface of the negative model.

The object on which the invention is based is seen in this, especially small structures dimensionally accurate from the mold core to the negative model and from there back to the embossing roller shell transferred, in particular the respective demolding should take place particularly gently.

This object is achieved by the fact that to apply the synthetic resin to the Mold core inserts the mold core concentrically into a forme cylinder, leaving an annular space free and the synthetic resin is poured into the annular space and that the negative model is separated from the Mold core the negative model with a firm bond to the forme cylinder and / or to separate the embossing roller jacket of the negative model cools the embossing roller shell and / or the negative model.

A second solution to this problem is characterized in that one for applying the synthetic resin on the mold core, the mold core leaving an annular space concentrically in one Form cylinder is used and the synthetic resin is poured into the annulus and that you have to separate the Negative model from the mold core and / or to separate the embossing roller jacket from the negative model Separates the negative model from the forme cylinder and causes it to swell using organic liquids.

The cooling of the negative model as well as the embossing roller jacket causes shrinkage in each case the same caused. Since the negative model adheres firmly to the forme cylinder, this leads to shrinkage an increase in its diameter so that it can easily be detached from the mandrel and removed from it can be. On the other hand, cooling of the embossing roller jacket that is firmly seated on the roller core leads to a reduction in the diameter of the latter, so that the embossing roller jacket detaches from the negative model. If you cool both, i.e. both the negative model and the embossing roller jacket, this leads to the Formation of a small ring gap, which is a slight Removal of the roll core with the embossing roll shell from the on its outer circumference firmly with the Enables the negative model connected to the forme cylinder.

It goes without saying that such a demolding takes place particularly gently, since the embossing roller shell is from the negative mode slowly and evenly dissolves under the influence of cooling, namely in a radial direction Direction, which is particularly important. Only when the roller core is removed coaxially with the embossing roller shell At most, slight shear stresses can occur in the axial direction, which of the size or depth of the structures in the embossing roller shell or in the negative model.

In the second solution to the problem of the invention, there is no permanent adhesion of the negative model on the inner wall of the forme cylinder, so that the negative model both during its production by means of of the mold core as well as in the manufacture of the embossing roller jacket on the roller core with the The mold core or the roller core and the embossing roller jacket can be removed from the forme cylinder and only after this is the negative model of the mold core or of the embossing roller jacket of the roller core This is done here by using organic liquids to convert the negative model Sources brings. This swelling of the negative model also leads to an increase in diameter, so that the negative model is detached from the mold core or later from the embossing roller shell and pulled axially ^ can. Here, too, the negative model is released from the mold core or from the embossing roller shell mainly in the radial direction (diameter enlargement), so that demolding is particularly gentle in any case.

• If one chooses the first alternative, i. H. the cooling of the negative jacket or the embossing roller jacket, then is it is particularly advantageous to make the mold core or the roller core hollow. In this case it can then not only the negative model, but also the embossing roller shell are cooled on both sides, d. H. both inside by introducing coolant into the hollow mold core or soles Roller core, as well as from the outside, from the outside of the forme cylinder, one softens in Brings into contact with a coolant. The oiling in the roller core provides an additional advantage in that than in the later Herjtellui.g of embossed plastic films can also work with a coolant to influence the films.

The invention and its advantageous embodiments are detailed below with reference to the drawing explained.

It shows

F i g. I a front view of a roller produced by the method according to the invention, with a part is shown in section to show the internal structure;

F i g. 2 shows a partial section of the roller on an enlarged scale;

F i g. 3 semi-schematically an apparatus for carrying out the method according to the invention, wherein Part "are shown in section to show the internal structure and the liquid resin during this is filled;

FIG. 4 is a schematic partial view similar to that in FIG F i g. 3, but on an enlarged scale, showing the cavities in the roller core and a primer coating shown greatly coarsened and an upper cover and a seal are removed; and

Fig.5 in a view similar to Fig.4 the Device during casting, with the primer coating and the protrusions on the negative impression are shown greatly enlarged.

In Figs. 1 and 2 of the drawings, one is after The embossing roller produced by the method according to the invention is shown, which has a roller core 10 made of metal

has, the cylindrical main part 12 with embossing * roll shell made of relatively elastic, deformable material 14 is coated, in which a plurality of substantially spherical-shell-shaped depressions 16 arranged closely spaced next to one another are located. As best seen in Fig. 1, is the cylindrical main part 12 of the roller core 10 is hollow and shows a chamber 18, which is a Can absorb heat exchange medium. Stub axles 20 extend from the ends of the main portion of FIG 'Embossing roller coaxially outwards and are stored in a roller stand (not shown). Through the Shaft journals extend through passages 22 that communicate with chamber 18 and through flowable medium can be passed.

In Figures 3 to 5 is a semi-schematic Apparatus for producing the embossing roller according to the method according to the invention. F i g. 3 shows a compound shape. A forme cylinder 24 has outwardly projecting flanges 26 at its ends. This forme cylinder has a bore 28. A mold core 30 is held coaxially in the bore 28 and has a main part 32, the diameter of which is smaller than the diameter of the wall of the forme cylinder, the defines the bore 28 so that an annulus remains around the core. A lid 34 and a bottom 36 close the mold cavity or the bore 28 and are connected to the flanges 26 by not shown Screws firmly connected, which are passed through corresponding holes. The bottom 36 has a feed opening 37, which is aligned with an extension of the annulus in the mold cavity 28.

The shaft journals 38 of the mold core 30 extend outward through openings in the cover 34 and the bottom 36, and seals 54 are between the cover 34 and the bottom 36 on the one hand, as well as the Mold core 30, on the other hand, is provided to prevent liquid from flowing out of the annulus at the ends of the main part 32 flows out and the impurities enter this annulus. The main part 32 of the Mold core 30 encloses a chamber 40. The shaft stubs 38 have passages 42 that with the Communicate chambers so that a heat exchange medium can be passed through the mandrel can.

A cylindrical jacket 44 extends around the forme cylinder 24 and has a larger inner diameter than this, so that an annulus 46 is formed. Seals 56 are between the ends of the shell 44 and the flanges 26 so that the ends of the cavity 46 are sealed. An inlet pipe 48 and an outlet pipe 50 are provided near the ends of the jacket 44 to allow a heat exchange medium through the To conduct cavity 46.

In order to allow air to escape, a vent 59 is provided in the cover 33. As shown schematically in Fig.3, the synthetic resin pumped by the pump 53 from the storage vessel 60 into the annular space through the supply line 62, in which is a valve 64. The storage vessel 60 has a removable lid 66 so that it is filled and can be cleaned. A line 68 from the vacuum pump 52 enables the evacuation of air from the storage container 60 with the valve 70 open and the lid 66 closed.

during operation of the one shown schematically in FIG Device is a mold core 30, which has the desired embossing pattern in the form of on its surface Embossings or cavities 33 around its circumference, as shown enlarged in FIG. 4, cleaned and fastened in the forme cylinder 24. In general, this mandrel 30 is made of metal and the Embossings of the pattern are engraved, etched or otherwise incorporated into the surface. Appropriately, the wall of the forme cylinder 24, the bore or the cylindrical Mold cavity 28 forms, with a primer

Jo treated that a thin coating 69 on the Forms mold wall and thus facilitates adhesion or bonding. This cover is enlarged Thickness in Fig. 3 shown. This can be achieved by flushing the forme cylinder 24 with the resin,

before the mold core part 30 is introduced. If first a primer coating on the forme cylinder 24 is applied, a resin can be used that only bonds with the primer so that no lost coating on the surface of the

2ö mold core 30 must be applied.

Synthetic resin in the reservoir 60 is placed under vacuum by the vacuum pump 52 via the line 68 by closing the lid 66 and opening the valve 70 so that the air is extracted from the mass. After the air has been removed from the synthetic resin, the vacuum pump is disconnected by closing the valve 70. In this way, a pi> renfre ^{: <} ; s material can be obtained. The pump 53 then pumps synthetic resin from the container 60 through the line 62 into the annular space between the mold core 30 and the forme cylinder 24, the valve 64 being opened and the air being able to be drawn off through the vent 59. This state is shown in FIG. 4 shown.

After the annular space in the forme cylinder 24 has been filled, the valve 64 is closed. Window (not shown) made of synthetic plastic or glass can be provided in the forme cylinder 24 to the watch correct filling. The forme cylinder 24 is rotated several times around the mandrel 30 by the upper flange 26 is turned over, thus ensuring the correct distribution of the resin 71 and its orientation in Direction of rotation of the embossing roller is guaranteed.

The resin 71 is then made by introducing a heated medium into the cavity 46 of the jacket 44 hardened. The medium is introduced from a source (not shown) via the inlet pipe 48. To that To accelerate hardening, the heated medium is also in the chamber 40 of the mold core 30 through the Passage 42 in the upper shaft stub 38 via a

Coupling not shown in this way is introduced The heat medium is then fed through connection lines, not shown, which are connected to the outlet pipe 50 and the lower shaft stub 38, fed back

After a sufficiently long exposure to heat, the flow of the heated heating medium is interrupted and the forme cylinder is cooled. Cold water is in the cavity 46 and the chamber 40 from a non water source shown in the same way as the heated medium introduced so that the resin, which is cured and connected to the wall of the molded part 24, shrunk away from the mold core 30. The cover 34 is then removed and the mold core 30 is removed from the cylindrical mold cavity 28. As in Fig. 5, the cured resin forms a negative mold 72 with a plurality of im

WcScniiiCiien iCBgciSCnaiCTliOi uiigcTi Eriicuüligcil 74 ^ UiC

are shown enlarged) on its surface, in the form of a pattern that corresponds to the pattern from the

Depressions 33 in the mold core 30 corresponds.

In the manufacture of the embossing rollers according to FIGS. 1 and 2 with elastic surfaces, the surface of the negative module 72 is expediently treated with a release agent; while the surface of the main part 12 of a roller core 10 is coated with a primer. The roller core 10 is arranged in the cavity 28, its shaft support 20 extending through the cover 34 and the base 36. The mold cavity 28 is closed tightly. Of the roll core 10 as shown in F i g <5 Get diameter of the main part 12 is smaller than the diameter of the negative model 72, su that an annular space is formed therebetween. The filling of the mold cavity 28 or annular space is repeated, preferably with a resin that adheres as little as possible to the hardened resin of the negative model 72. First, the mass of the liquid resin in the storage vessel 60 is evacuated. The resin 76 is then introduced into the mold cavity via line 62 to fill the annulus between the negative pattern 72 and the main portion 12 of the roller core 10, as shown in FIG. 5 shown. The form cylinder 24 is then rotated several times by inverting the top flange 26 to ensure proper distribution and orientation of the resin. A heated heat medium from a corresponding supply source (not shown) is passed through the inlet and outlet pipes 48 and 50 through the annular space 46 of the shell and through the chamber 18 of the roller core 10 by means of the passages 22 in the shaft connector 20.

After a sufficiently long time required for the resin 76 to cure, the The flow of the heated heating medium is interrupted and cooling liquid is introduced to prevent the shrinkage of the To cause resin to bond to the surface of the main part 12 of the roller core 10 top lid 34 is removed and alcohol, air, or other medium is allowed into mold cavity 28 be introduced through the opening 37 in order to ensure a good separation of the coating 14 from the negative model 72 facilitate. The roller is then removed from the mold cavity 28 and can be hardened further or treated as it is for the production of the in Figs. 1 and 2 shown roller is required «

As mentioned above, the method according to the invention for producing the in the drawings Embossing rollers illustrated are used to make plastic rollers with different types of surfaces to create. However, the invention can also be used to manufacture rolls with a highly polished, Mirror-like, relatively elastic coating are used for the production of films with a yoke-polished surface are suitable. It can be a Mold core with a highly polished outer surface can be used to make a negative model with a to produce highly polished inner surface. This negative model can in turn be used for the production of a Find an embossing roller with a coating that has a highly polished, elastic surface '°°

Different synthetic resins can be used for the production of both the negative model and the elastic Embossing roller jacket, such as silicone rubber, polyurethanes and synthetic rubbers, such as B. polybutadienes, and interpolymers of butadiene with other ethically unsaturated monomers, such as styrene, acrylonitrile, acrylates and methacrylates, polyisoprenes, terpolymers made from ethylene and propylene. In general, the resins should have a Shore hardness of 50 to 100 and preferably from 60 to Have 85 on the Shore ^ scale. The resins that are suitable from the standpoint of durability, functional The best hardness, malleability and temperature resistance are the silicones. That particular polymers, and even the properties of a particular polymer, will vary with the one desired Application and the desired hardness. The resin should have a relatively pore-free surface cure and have a fairly high solvent resistance. As detailed below are resins which have a relatively high coefficient of thermal expansion from the standpoint of lightness Production of the rollers advantageous.

The time for the resin to harden and solidify is dependent on the particular resin as well as depending on the temperature. In general, these factors are based on the information provided by the manufacturers of the products refer to. Resins that crosslink should be allowed to cure through and through before being used on anyone to avoid adverse effects on the surface of the synthetic resin coating on the roller.

A resin can be used for the negative model that is different from that used for the embossing roller shell used differs, and this can offer certain advantages by replacing the Resin cast against the negative model is facilitated. In addition, it is sometimes desirable to make the coating thickness on the roll core from two layers of different resins in order to to get all of their properties in the coat. For example, the lower layer can be relative elastic and the overlying layer relatively stiff, with the entire coating to the desired extent In addition, the hardness of a particular resin can be increased through the use of elasticity Fillers are enlarged in a known manner.

To ensure complete bonding of the resin with the surface of either of the forme cylinder defining Wall or the roller core depending on. of the respective stage of the procedure, the Surface of the underlying metal thoroughly cleaned and removed to remove grease and dirt expediently be coated with a primer that is suitable for the particular resin used is. Primers have been found to be particularly beneficial with silicone resins, and so have manufacturers these silicone resins provide suitable undercoats or primers for their various products at.

The primers can be applied as desired. When applying the primer to the surface the mold cylinder wall, the mold can first be sprayed with the primer before the mold core is introduced. Alternatively, the primer can be applied by brushing, rolling, spraying or the like. be applied. These techniques can also be used for the treatment of the roll core, before it is inserted into the forme cylinder. The roller core can also be bathed from the Primer to be rotated. The thickness of the primer varies with the effectiveness of the same and'den Regulations of the individual manufacturers, which are announced by them for the maintenance of the best results will. In some cases the Voransirich be pre-cured according to its chemical composition and the manufacturer's instructions.

The mold core is most expediently removed from the negative model by cooling the negative model in order to cause the same to shrink which is sufficient to allow the mold core to be easily removed. Another, also preferred method uses a negative model that is not connected to the wall of the forme cylinder, so that it can be removed from the forme cylinder together with the mold core and stretched thereon, for. B. can be made to swell by using suitable organic liquids. Likewise, the embossing roll shell cast on the roll core can be separated from the negative model using the thermal contraction or shrinkage of the resin. The main advantage here is the shrinkage of the negative model, although the shrinkage of the embossing roller shell on the roller core, depending on the thickness of this shell, is also significant; in general, however, the negative mode is considerably thicker than the embossing roll shell. In addition, the negative model together with the roller core and the embossing roller shell can be removed from the forme cylinder and the embossing roller shell can then be pulled out of the negative model by stretching it by swelling or the like.

In order to give the surface optimal properties, it is necessary to apply heat to the resin very important. First, the resin should be heated to a temperature slightly below that in which rapid curing takes place, so that practically all of the expansion of the resin is still in the flowable state takes place, whereby the liquid resin can be distributed in the mold cavity without Large prints must be applied to the surface of the form and roller and a flow of the solidified resin is avoided.

The temperature of the resin is then increased to cause the solidified resin to expand and to shift the shrinkage that occurs during the solidification or during the curing of the Harz takes place. The temperatures and times vary depending on the particular one used Resins, as is well known. It is intended that most of the stretching of the resin will do effect before substantial solidification takes place, so that shrinkage occurs during curing the resin is shifted with an increase in temperature with further expansion at the same time. On that the resin can be kept at the same or slightly higher temperature so that it is in the mold hardens or the parts can be separated from each other and the resin at a much higher temperature exposed so that hardening takes place in a shorter period of time. Too great thermal expansion, While the parts are still in the mold, excessive pressures can cause deformation and have a flow of the solidified resin result, so that excessively high temperatures after solidification of the Resin and while it is still in the mold should not be used.

In one embodiment according to the invention, the embossing roller shell is not connected to the roller core during casting, but later to the same or a different roller core so verbunrian HoR oma VorfArmnn » Α · λγ- _η ..Γ An ~~ D - ::» η— * »1— ~ ->
uwij, WUm wiiiw TbIiVIlIlUlIg UwO aUi UwIIl 1 lagCTTOUCtr shell molded, raised pattern is prevented. With this particular technique it is advisable to insert support rings at the top and bottom of the hollow space inside the negative model, which are coated with a primer or otherwise treated so that a connection of the resin from which the embossing roller maritel is formed with these support rings is easier will. These support rings facilitate the later handling of the embossing roller jacket and its arrangement in other devices. With this technique, the roller core and the embossing roller shell with the ring supports are removed from the mold. The imprint can then be stretched in the axial direction over the same roller core or a different one in order to increase the axial distance between the individual embossed elements and thereby cause a deformation of the pattern from these elements. The impression can also be stretched in the circumferential direction around a support or core that has a larger diameter.

_ ser has so that the distance between the elements of the embossing tinter a corresponding deformation of the pattern in Circumferential direction is increased. In yet another method, either or both ends of the Imprint rotated in the circumferential direction around the roller core, so that a pattern of helical sinuous embossing arises. This means that the most varied of them can be produced from a single negative model Embossing patterns can be obtained on roller cores.

The thickness of the coating on the roller core should be so great that the desired elasticity is obtained, however, it should not be so great that it prevents sufficiently effective heat exchange through the coating will. In general, the thickness of the embossing roll shell is on the order of 1.6 to 12.7 and preferably from 2.4 to 6.3 mm

For a sufficient thickness of the negative model, so that the separation can take place by shrinking, should the resin coating in the form cylinder is about 6.3 to 38 mm and preferably about 3.2 to 25.4 mm. It Though greater thicknesses can be used, the benefit obtained thereby is small and some Problems can arise when pouring thicker layers. Nevertheless, the layer thickness !, can be greater than 2.54 cm can be used for some purposes, especially when the diameter of the mold cavity is relatively large, d. H. larger than about 25 cm.

The method according to the invention has proven to be particularly advantageous for producing embossing rollers with relatively small contours on their surfaces. An example of the effect of the method according to the invention is its use in the manufacture of embossing rollers as are necessary to manufacture the optically active sheet material described in US Pat. No. 3,357,772, a plurality of very small, lens-shaped Bumps on one surface are in phase but not in axial alignment with a plurality of reflective bumps on the other surface of the sheet material.
The invention is explained further on the basis of the following examples

A shape is used as shown in FIG. 1 is shown, with a mold cavity, the axial Length 172.7 cm and its diameter is about 17.8 cm. The mold core is in this particular case an engraved steel roller with a hexagonal pattern of indentations in the surface that are in the essentially the shape of spherical shells with a diameter of about 0.2540 mm and a depth of

about 0.1524 mm. The roller core has an axial one Length of 167.64 cm and an outside diameter of approximately 15.24 cm. After thorough cleaning, a Relatively thin wax coating applied as a separating agent to the surface of the same.

Before the mold core is inserted into the mold cavity, the wall of the mold cylinder is blown with a sandblast sandblasted, cleaned with a solvent and then with a coating of a silicone base agent primed (SYLGARD from Dow-Cor-

With a mass of silicone resin (RTV-630 from General Electric Company) is placed in a storage jar along with 10 parts by weight based on the weight of the Resin, a hardening agent (630 B from General Electric Company) This mixture is placed under a vacuum of 2 torr for about 1 hour exposed to remove gas and volatiles from the mixture. ...

Thereupon the vacuum is interrupted and compressed air is introduced into the storage vessel, whereby the relative Viscous resin from the vessel into the annulus "wipe the mold core and the wall of the forme cylinder is transported Sufficient resin is filled in so that the annulus is practically complete is full, but about 38 mm of air space is left at the top of the mold. The shape then becomes multiple Times twisted relative to the core, thereby orienting the coating in the circumferential direction around the Core causes and streaks are eliminated, while at the same time homogeneity of the resin is achieved.

A heat medium is then introduced into the jacket around the mold and to the chamber in the mold core at a Temperature of 4333 ° C passed for 15 minutes and then the temperature of the heating medium to 62.78 ° C increased over a period of 20 minutes and an additional 45 minutes at that temperature maintain. During this period of time, the resin, which is still liquid, expands in the mold cavity and so completely fills the air space at the top of the mold cavity. The resin then solidifies. Since the Solidification causes a contraction or shrinkage of the resin volume, the temperature of the Heat medium raised to 65.56 "C to a To obtain compensation thermal expansion of the resin. The resin is at this temperature for 8 hours held, during which time the resin completely solidifies and its initial hardening takes place

The temperature of the heating medium is then reduced to about 7.22 ° C and the cooling flow is continued for about 30 minutes to cause the thermal contraction or shrinkage of the resin forming the negative pattern on the inner surface of the forme cylinder. The lid of the mold is then removed ^: and 250 ° C denatured alcohol is poured into the annulus between the negative model and the surface of the mold core to facilitate separation. The alcohol penetrates the depth of the mold and serves as a lubricant and release agent

the mold core can easily be pulled outwards from the negative model.

A coating of a high-temperature wax separating agent is then applied to the surface of the model. »Has shaft stubs extending outward from the ends of the main part, is cleaned and primed with the primer on the surface of the main part. The roller core is centered in the cavity of the negative model and the cover is put on. A silicone resin composition (RTV-630 of Messrs. General Electric Company) and 10 wt. ^N / o, based on the weight of the resin, a curing agent (630B of Messrs. General Electric Company) are charged into the storage vessel and a vacuum of about 2 ίο Exposed to torr for about 1 hour. The resin is then pressurized to about 1.9 atmospheres and placed in the annulus between the roller core and the negative pattern in an amount sufficient to fill the entire mold cavity with the exception of about 38 mm at the top of the mold cavity

The roller core and the forme cylinder are rotated relative to each other several times to the Orientation of the viscous resin in the direction of roll rotation and around in the axial direction to remove running streaks. A heating medium is introduced into the mold jacket and the chamber of the Roll core with a temperature of 43.33 ° C for 10 minutes Mold jacket is passed, is then further heated to a temperature of about 62.78 ° C and on this Maintained temperature for about 45 minutes while the flow of the heat transfer medium through the roller core Is interrupted. This increases the heat transfer medium that is fed to the shell of the mold Temperature of the negative model gradually; then the temperature of the liquid resin and the roller core elevated. This gradual increase in the temperature of the liquid resin has the gradual thermal expansion of the negative model and also the strong stretching of the liquid resin.

The temperature of the heat medium, data Mold jacket is fed, is then increased to 65.56 C and then the heat medium flow to the Waizenkern switched on again to raise the temperature of the core to 65.56 "C. As a result, the Shrinkage of the liquid resin, which takes place through solidification, strong through the thermal Expansion of the same compensated, so that the surface of the solidifying resin, which creates the positive firn imprint of the embossing roller jacket, remains in close contact with the surface of the negative model. This is extremely important because it enables optimal reproducibility of the pattern. Of the Heat medium flow is continued for approximately 8 hours at a temperature of 65.56 ° C to achieve a to bring about complete curing of the resin on the surface of the roller core.

Then a coolant having a temperature of about ⁰ C 7.22 in the mold shell and into the roll core is about 45 minutes led to a cooling and thermal contraction of both the negative model and to obtain the embossing roll mantle. The lid is removed and denatured alcohol is poured between the negative model and the ω embossing roller jacket to facilitate the separation of the two. The roll core is then pulled out of the negative model and viewed under magnification. It is found that the surface of the embossing roll shell had a plurality of essentially card-shaped depressions which practically corresponded to the pattern and the spacing of the original roll.

For this purpose 2 sheets of drawings

Claims (14)

Patent claims: 1. A method for producing an embossing roller for thermoplastic plastic films, in which one on a cylindrical mold core with a shape identical to that of the embossing roller to be produced the outer surface applies a synthetic resin and at elevated temperature to form a elastic negative model, which is separated from the mold core, cures into the negative model Release of an annular space concentrically inserts a roller core, in the annular space a synthetic resin pours, the synthetic resin hardens under heat to form an elastic embossing roller shell and the Separates the roller core together with the embossing roller shell from the negative model, characterized in that that to apply the synthetic resin to the mold core, the mold core leaving an annular space concentrically in a Form cylinder is used and the synthetic resin is poured into the annulus and that you have to separate the Negaiivmodelis from the mold core the negative fashion !! with a firm bond to the forme cylinder and / or to separate the embossing roller jacket from the negative model, the embossing roller jacket and / or the Negative model cools. 2. A method for producing an embossing roller for thermoplastic plastic films, in which one on a cylindrical mold core with a shape identical to that of the embossing roller to be produced a synthetic resin is applied to the outer surface and at an elevated temperature to form a elastic negative model ai "= hardens that one from Mold core separates, concentrically in the negative model, leaving an annular space free Roll core inserts, a synthetic resin is poured into the annular space, the synthetic resin under heat to one elastic embossing roller shell hardens and the roller core together with the embossing roller shell separates from the negative model, characterized by -to that to apply the synthetic resin to the mold core, the mold core while releasing a The annular space is inserted concentrically in a forme cylinder and the synthetic resin is poured into the annular space and that for separating the negative model from the mold core and / or for separating the embossing roller jacket from the negative model separates the negative model from the forme cylinder and using organic liquids brings to the source. 3. The method according to claim 1 or 2, characterized in that there is at least as synthetic resin a silicone resin is used for the embossing barrel. 4. The method according to any one of claims 1 to 3, characterized in that for relief the separation of the embossing roller casing. introduces a release agent from the negative model. 5. The method according to any one of claims 1 to 4, characterized in that there is a mold core used with a highly polished surface. 6. The method according to any one of the preceding claims, characterized in that the embossing roller shell is firmly connected to the roller core during the curing of the synthetic resin. 7. The method according to any one of claims 1 or 3 to 6, characterized in that the inner Surface of the forme cylinder and the surface of the roller core before the synthetic resins are filled Treated with a primer in the appropriate annular spaces to ensure the adhesion of the To improve synthetic resins, 8. The method according to any one of the preceding claims, characterized in that one Applying release agent to the surface of the negative model to prevent adhesion of the in the annulus to prevent synthetic resin filled between the negative model and the roller core. 9. The method according to any one of the preceding claims, characterized in that the The roller core and the negative model rotates relative to one another when the synthetic resin is poured in, by one To effect orientation of the synthetic resin in the direction of rotation of the embossing roller. 10. The method according to any one of the preceding claims, characterized in that the flowable synthetic resin before filling into the annulus for the purpose of removing air and exposes other gases from it to a vacuum 11. The method according to any one of the preceding claims, characterized in that the in the annular space between the mold core and the forme cylinder to form the negative model The synthetic resin filled in is first heated to a temperature slightly below that at which the Resin cures to cause elongation thereof while it is nocif liquid, and that you then heated the resin further, choosing the temperature change so that a Shrinkage of the resin from curing is compensated for. 12. The method according to any one of the preceding claims, characterized in that the Strips the embossing roller shell from the roller core and applies it to another roller core. 13. The method according to claim 12, characterized in that the embossing roller shell below Change of the grid spacing of the embossing in the axial direction via an av its roller core is extended. 14. The method according to claim 12, characterized in that the embossing roller shell with the embossed surface for generating a rotated pattern in the axial direction around the other roller core rotates.